Overestimation and underestimation of patient blood loss is a significant contributor to high operating and surgical costs for hospitals, clinics and other medical facilities. Specifically, overestimation of patient blood loss results in wasted transfusion-grade blood and higher operating costs for medical institutions and can lead to blood shortages. Underestimation of patient blood loss is a key contributor of delayed resuscitation and transfusion in the event of hemorrhage and has been associated with billions of dollars in avoidable patient infections, re-hospitalizations, and lawsuits annually. Uninformed estimation of varying patient hematocrit during hemorrhage, blood transfusion, and intravenous saline infusion further exacerbates inaccurate estimation of patient red blood cell loss and negatively impacts the timing and quantity of fluids supplied to a patient intravenously. Thus, there is a need in the surgical field for a new and useful system and method for managing blood loss of a patient. This invention provides such a new and useful system and method.